System and method for protecting engine fuel pumps

Abstract

A fuel control system for an internal combustion engine includes a fuel starvation detection module and a fuel pump protection module. The fuel starvation detection module detects when a fuel pump is delivering less than a predetermined amount of fuel based on a fuel level in a fuel tank, a fuel pressure in the fuel pump, and an air/fuel (A/F) ratio of the engine. The fuel pump protection module decreases an amount of fuel supplied to the engine during a period after detecting that the fuel pump is delivering less than the predetermined amount of fuel.

1. A fuel control system for an internal combustion engine, comprising:
 a fuel starvation detection module that detects when a fuel pump is delivering less than a predetermined amount of fuel based on a fuel level in a fuel tank, a fuel pressure in the fuel pump, and an air/fuel (A/F) ratio of the engine; and 
 a fuel pump protection module that decreases an amount of fuel supplied to the engine during a period after detecting that the fuel pump is delivering less than the predetermined amount of fuel. 
 
     
     
       2. The fuel control system of  claim 1 , wherein the fuel starvation detection module detects when the fuel level in the fuel tank is less than a predetermined fuel level. 
     
     
       3. The fuel control system of  claim 2 , wherein the fuel starvation detection module detects when the fuel pressure in the fuel pump is less than a predetermined pressure for a first predetermined period. 
     
     
       4. The fuel control system of  claim 3 , wherein the fuel pressure in the fuel pump includes a difference between a desired fuel pressure and an estimated fuel pressure, and wherein the fuel starvation module detects when the difference is less than the predetermined pressure for the first predetermined period. 
     
     
       5. The fuel control system of  claim 3 , wherein the fuel starvation detection module detects when the A/F ratio of the engine is greater than a predetermined A/F ratio for a second predetermined period. 
     
     
       6. The fuel control system of  claim 5 , wherein the A/F ratio of the engine is determined based on a signal from an oxygen sensor indicating an amount of oxygen in exhaust gas produced by the engine, and wherein the fuel starvation detection module detects when the signal is greater than a predetermined voltage for the second predetermined period. 
     
     
       7. The fuel control system of  claim 5 , wherein the fuel starvation detection module detects that the fuel pump is delivering less than the predetermined amount of fuel when the fuel level in the fuel tank is less than the predetermined fuel level, when the fuel pressure in the fuel pump is less than the predetermined pressure for the first predetermined period, and when the A/F ratio of the engine is greater than the predetermined A/F ratio for the second predetermined period. 
     
     
       8. The fuel control system of  claim 1 , wherein the fuel pump protection module disables fuel correction and decreases the amount of fuel supplied to the engine during the period until the engine stalls, and wherein the fuel starvation detection module is reset when one of an engine start event, and engine stop event, and a stall of the engine occurs. 
     
     
       9. The fuel control system of  claim 5 , wherein the fuel pump is a low pressure fuel pump that pressurizes and pumps fuel from the fuel tank, wherein purging of a fuel vapor canister is enabled when one of the fuel level is greater than the predetermined fuel level and the fuel pressure is greater than the predetermined pressure, and wherein purging of the fuel vapor canister is disabled when the fuel pressure is less than the predetermined pressure. 
     
     
       10. The fuel control system of  claim 9 , further comprising:
 a high pressure fuel pump that receives the pressurized fuel from the low pressure fuel pump, that further pressurizes the pressurized fuel, and that supplies high pressure fuel to a plurality of fuel injectors in a plurality of cylinders of the engine, respectively, 
 wherein the engine is a spark-ignition, direct-injection (SIDI) engine, and wherein the high pressure fuel pump is disabled when the fuel level in the fuel tank is less than the predetermined fuel level, when the fuel pressure is less than the predetermined fuel pressure for the first predetermined period, and when the A/F ratio of the engine is greater than the predetermined A/F ratio for the second predetermined period. 
 
     
     
       11. A method, comprising:
 detecting when a fuel pump is delivering less than a predetermined amount of fuel based on a fuel level in a fuel tank, a fuel pressure in the fuel pump, and an air/fuel (A/F) ratio of an engine; and 
 decreasing an amount of fuel supplied to the engine during a period after detecting that the fuel pump is delivering less than the predetermined amount of fuel. 
 
     
     
       12. The method of  claim 11 , further comprising:
 detecting when the fuel level in the fuel tank is less than a predetermined fuel level. 
 
     
     
       13. The method of  claim 12 , further comprising:
 detecting when the fuel pressure in the fuel pump is less than a predetermined pressure for a first predetermined period. 
 
     
     
       14. The method of  claim 13 , further comprising:
 detecting when a fuel pressure difference is less than the predetermined pressure for the first predetermined period, wherein the fuel pressure difference includes a difference between a desired fuel pressure and an estimated fuel pressure in the fuel pump. 
 
     
     
       15. The method of  claim 13 , further comprising:
 detecting when the A/F ratio of the engine is greater than a predetermined A/F ratio for a second predetermined period. 
 
     
     
       16. The method of  claim 15 , further comprising:
 detecting when a signal is greater than a predetermined voltage for the second predetermined period, 
 wherein the signal is from an oxygen sensor indicating an amount of oxygen in exhaust gas produced by the engine, and wherein the A/F ratio of the engine is determined based on the signal. 
 
     
     
       17. The method of  claim 15 , further comprising:
 detecting that the fuel pump is delivering less than the predetermined amount of fuel when the fuel level in the fuel tank is less than the predetermined fuel level, when the fuel pressure in the fuel pump is less than the predetermined pressure for the first predetermined period, and when the A/F ratio of the engine is greater than the predetermined A/F ratio for the second predetermined period. 
 
     
     
       18. The method of  claim 11 , further comprising:
 disabling fuel correction and decreasing the amount of fuel supplied to the engine during the period until the engine stalls; and 
 resetting the detecting of when the fuel pump is delivering less than the predetermined amount of fuel when one of an engine start event, and engine stop event, and a stall of the engine occurs. 
 
     
     
       19. The method of  claim 15 , wherein the fuel pump is a low pressure fuel pump that pressurizes and pumps fuel from the fuel tank, wherein purging of a fuel vapor canister is enabled when one of the fuel level is greater than the predetermined fuel level and the fuel pressure is greater than the predetermined pressure, and wherein purging of the fuel vapor canister is disabled when the fuel pressure is less than the predetermined pressure. 
     
     
       20. The method of  claim 19 , further comprising:
 receiving the pressurized fuel from the low pressure fuel pump; 
 further pressurizing the pressurized fuel using a high pressure fuel pump; and 
 supplying high pressure fuel to a plurality of fuel injectors in a plurality of cylinders of the engine, respectively, 
 wherein the engine is a spark-ignition, direct-injection (SIDI) engine, and wherein the high pressure fuel pump is disabled when the fuel level in the fuel tank is less than the predetermined fuel level, when the fuel pressure is less than the predetermined pressure for the first predetermined period, and when the A/F ratio of the engine is greater than the predetermined A/F ratio for the second predetermined period.